An ultra-quick electric current breaker device is known, wherein an insulating member acting as a punching piston is pushed by a pyrotechnical charge in such manner as to sever a destructible electric conductor. The displacement of this piston is generally transverse with respect to the conductor, but it may also be provided as longitudinal. In such a case the destructible conductor includes an upstream portion having the shape of a socket in which the punching piston slides, the outer side of the bottom of this socket extending as an intermediate portion which is slidably engaged into the bore of a downstream portion disposed at a certain distance from this bottom, the three portions being co-axial with respect to each other. When the charge explodes the punching piston severs the bottom of the socket to separate therefrom the intermediate portion which it pushes into the bore of the downstream portion.
The invention aims at improving the devices of this kind.